Carcharhinus signatus
Carcharhinus signatus (''Night shark)' Kingdom: '''Animalia Phylum: Chordata Class: Chondrichthyes Order: Carcharhiniformes Family: Carcharhinidae Genus: Carcharhinus Species: Carcharhinus signatus Environment: milieu, climate zone, depth range, distribution range: Marine; benthopelagic; depth range 0 - 600 m, usually 50 - 100 m. Subtropical; 11°C - 16°C; 39°N - 43°S, 85°W - 15°E. Distribution: Western Atlantic: Delaware to Florida (USA), Bahamas, and Cuba; southern Brazil, Argentina. Eastern Atlantic: Senegal to Côte d'Ivoire, Ghana to Cameroon, Democratic Republic of the Congo, Angola, off northern Namibia. Size, weight, age: Max. length: 2.80 m, common length: 2 m; weight: 76.7 kg; age: ?''' ''Short description:'' The night shark has a slender build with an elongated, pointed snout. The nares are flanked by moderately developed flaps of skin. The eyes are large, circular, and green in life, with irregularly shaped pupils and a nictitating membrane (protective third eyelid). The mouth lacks conspicuous furrows at the corners and usually bears 15 tooth rows on either side of both jaws, plus 1–2 upper and 1 lower symphysial (jaw midline) tooth rows. Each upper tooth has a smooth to serrated edge, a narrow cusp becoming more oblique towards the corner of the mouth, and 2–5 coarse serrations at the base of the trailing margin. The number and size of serrations on the leading margin of the tooth cusp increase relative to those on the trailing margin as the animal grows older. The lower teeth are upright and smooth-edged. The five pairs of gill slits are rather short. The pectoral fins are less than a fifth as long as the total body length and taper towards a somewhat rounded tip. The first dorsal fin is relatively small, triangular, and pointed, originating over the free rear tips of the pectoral fins. The second dorsal fin is much smaller than the first and originates over or slightly ahead of the anal fin. There is a ridge running between the dorsal fins. The dermal denticles are not tightly packed and overlap each other minimally. Each denticle is diamond-shaped with horizontal ridges leading to marginal teeth, the number increasing from 3 in juveniles to 5–7 in adults. The coloration is grayish blue or brown above and whitish below, without fin markings. There is a faint band on each side and sometimes small black spots scattered over the back. This species usually grows to 2.0 m (6.6 ft) long, but has been recorded reaching a length and weight of 2.8 m (9.2 ft) and 76.7 kg (169 lb) respectively. ''Biology:'' Coastal and semi-oceanic species found on or along outer continental and insular shelves. Found to depths of 40 m. Forms schools. Nocturnal, and feeding mainly on small bony fishes and squid. Viviparous. Off West Africa, recorded water parameters at 90 to 285 m, where it was caught includes: temperature = 11 to 16°C; salinity = 36 ppt; oxygen = 1.81 ml/l. Not known to be dangerous to people. ''Life cycle and mating behavior:'' Viviparous, placental, with 4 to 12 young in a litter. Size at birth about 60 cm. Distinct pairing with embrace. ''Main reference:'' '''Compagno, L.J.V., 1984. FAO Species Catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 2 - Carcharhiniformes. FAO Fish. Synop. 125(4/2):251-655. Rome: FAO IUCN Red List Status: Data deficient (DD) CITES: Not Evaluated CMS: Not Evaluated Threat to humans: Harmless Human uses: Fisheries: commercial. Category:Carcharhinidae, Sharks